Current wireless cellular systems like GSM, UMTS, LTE, CDMA2000, WiMAX etc. support multiple mobile devices (e.g. phones, data cards/modems) where each device is associated with both physical-related identities and subscription-related identities. The subscription-related identities can either be stored in a Subscriber Identity Module (SIM) or directly in the mobile device (hard coded or configurable).
It is expected that the number of devices which are capable of connecting to cellular networks, sending and receiving data, will increase in the future. It is technically possible to install cellular modems in a number of portable and stationary electronic devices, e.g. cameras, ebook readers, TV/media players, fire alarms, electricity meters and other sensors. The possibilities are limitless. This offers great opportunities for cellular operators in the future to earn revenues from providing network access for these devices.
Traditionally mobile data and voice subscriptions have relied on pay per use charging (e.g. per minute, per megabyte, etc). However, the current trend is to rely more and more on flat-rate charging with unlimited or limited use at a fixed price per time unit (e.g. per month), or service-based charging where the cellular data transport is included in the service price (e.g. the price for a downloaded electronic book or song). From an end user point of view these charging methods are often preferred since they give predictability as to how much the service will cost.
Currently there is limited technical support for operators who want to offer their subscribers the possibility to connect multiple devices to their networks with some charging model which is deemed acceptable both for the operator and the end users in a reliable way.
It is assumed that the operator would like to charge more to end users who have multiple devices compared to those with just a single device. On the other hand, the end users would only accept these extra charges if they are reasonable. For example, one possible charging model would be for the operator to charge a basic subscription fee (for all users) and then a small reoccurring fee for each extra device that the user has. Other charging models can also be considered.
These charging models are possible to support in today's cellular networks; however, there is limited support for preventing abuse of the system, for example by an end user sharing or selling subscriptions with other users. If an end user has two devices which both have a cellular modem and are allowed to operate in parallel, how does the operator prevent the end user from lending or selling one of the devices to another person? This problem will grow in magnitude in the future as the number of devices that support cellular access increases.
One method to prevent such an abuse could be to limit the devices to only access specific services for which abuse is not an issue. An example of this could be a portable ebook reader which only allows access to a book seller's web site. A similar solution is possible for digital cameras, fire alarms etc. A problem arises, however, when the devices allow access to any service (e.g. the internet).